Fig. 3

Melanoma cell-secreted exosomes regulate the proangiogenic switch of CAFs via SOCS1/JAK2/STAT3 signaling pathway. a Treatment with B16- and B16F10-secreted exosomes elevated the phosphorylation levels of JAK2 and STAT3 and suppressed the expression of SOCS1. The ratio of the expression of SOCS1 and the phosphorylation levels of JAK2 and STAT3 are indicated below the panels. b Western blotting of nuclear P-STAT3 expression. The nuclear protein Histone H3 was used as the nuclear protein marker. c Treatment with AG490 downregulated the mRNA expressions of VEGFa, MMP9, and FGF2 in CAFs. * P < 0.05, ** P < 0.01, *** P < 0.001. One-way ANOVA and student’s t-tests. d, e Treatment with AG490 downregulated the phosphorylation levels of JAK2 and STAT3, and the expressions of VEGFa, MMP9, and FGF2 in CAFs. f, g The promotive effect of the CM from NIH/3T3 cells treated with B16- and B16F10-secreted exosomes on MS-1 cell proliferation was blocked by AG490. * P < 0.05, ** P < 0.01, *** P < 0.001 vs. the CM from NIH/3T3 cells; # P < 0.05, ## P < 0.01 vs. the CM from NIH/3T3 cells treated with B16- and B16F10-secreted exosomes. h, i, and j The promotive effects of the CM from NIH/3T3 cells treated with B16- and B16F10-secreted exosomes on MS-1 cell migration and tube formation were blocked by AG490. * P < 0.05, ** P < 0.01. Independent experiments performed in triplicate. Values are expressed as means ± SEM. One-way ANOVA and student’s t-tests. Scale bar, 50 μm. CAFs: cancer-associated fibroblasts. CM: conditioned medium. Exo: exosomes. FGF2: fibroblast growth factor 2. GAPDH: Glyceraldehyde 3-phosphate dehydrogenase. JAK2: Janus kinase 2. MMP9: matrix metalloproteinase 9. SEM: standard error of the mean. SOCS1: suppressor of cytokine signaling 1. STAT3: signal transducer and activator of transcription 3. VEGFa: vascular endothelial growth factor A